1. Field
This disclosure relates generally to semiconductor devices and methods of making the same, and more specifically, to a semiconductor device having metal carbide gate containing an electropositive element and a method of making the same.
2. Related Art
Semiconductor devices having metal gates and high-K gate dielectrics have a high threshold voltage resulting in lower effective drive currents and degraded short channel characteristics. Threshold voltages of N-channel devices can be lowered by reducing the work function of the gate layer. It has been shown that the threshold voltage can be lowered by adding compounds, such as magnesium oxide to the gate dielectric layer. While the addition of such compounds helps in lowering the device threshold voltage, the effective oxide thickness of the gate stack increases limiting device scaling. Minimizing the effective oxide thickness has been the predominate path to performance improvements for many years and is required for device scaling. In addition, the presence of magnesium oxide will make any dual-metal gate integration scheme more challenging since the magnesium oxide layer would need to be removed from the P-channel regions without adversely affecting the high-K gate dielectric material.
Accordingly, there is a need for a semiconductor device having a metal carbide gate containing an electropositive element and a method of making the same.